Tony Blair's defeat in the Commons has raised a number of questions about his future and that of the government's anti-terror legislation:

What has Tony Blair been defeated on?

Plans to allow police to detain terror suspects for up to 90 days without charge, rather than the existing 14 days. MPs have voted instead to extend the time limit to 28 days. In total 49 Labour MPs voted against the government including 12 former ministers.

The government's Terrorism Bill is still likely to become law - most of the measures contained in it are backed by MPs on all sides. But it still has to clear the House of Lords, where other controversial aspects, such as the "glorification" or indirect incitement of terrorism, are likely to face stiff opposition.

What does it mean for Tony Blair?

He will not have to resign as Labour leader or prime minister but it will be seen as weakening his authority. It is the first time his government has been defeated on a whipped vote - one in which MPs are told how to vote - since coming to power in 1997. The indication that enough Labour MPs are willing to rebel suggests he faces a battle to get through other parts of his third term programme, such as city academies, reform of incapacity benefit and pensions reform.

Does it mean he will have to call a general election?

No. The opposition parties could table a vote of no confidence - potentially triggering a general election - but Mr Blair has a big enough majority to win such a vote. Mr Blair told MPs at question time on Wednesday: "Sometimes it is better to lose and do the right thing than to win and do the wrong thing."

So what are Mr Blair's prospects?

The prime minister has said he will serve a full third term and then stand down before the next general election, due at any time up to May 2010. However the defeat will almost inevitably increase pressure for his departure to come sooner rather than later.

What happened the last time prime ministers were defeated?

The Major government of 1992 to 1997 suffered four defeats on whipped votes. Two were connected to the Maastricht treaty on closer European union, a third to an EU fisheries motion and another to VAT on fuel. Mr Major won a confidence vote and was able to serve out a full term before suffering a huge general election defeat. The last time a Labour government was defeated as a result of a backbench rebellion was 22 March 1979, just a few days before Jim Callaghan's minority administration fell.